There are many and varied patterns on the internet and on Ravelry for crochet baubles. I have been using the pattern by Carmen Hefferman (anniedesigncrochet on Instagram) in my copy of Boho Crochet edited by the late Marinke Shrimp. Carmen has also made this pattern available for free via her Ravelry store.
If you can work chain and treble stitches then you can work this pattern very easily - so it is an ideal project for a beginner.
The pattern calls for a DK-weight yarn and I have seen all kinds of yarn being used for baubles - they are great stash busting projects. Heather from The Patchwork Heart has been making heaps of baubles for her Etsy shop using Rico Essentials Cotton (DK); it is a mercerised yarn with good stitch definition that looks really attractive on a finished bauble.
I completely copied Heather's choice of yarn type but decided to keep to a really tight seasonal colour palette. The yarns above are; Teal, Silver and Ice Blue.
My friend S and I enlisted her husband to buy us a pack of baubles from a store called B&M during a visit to a nearby city. He kindly obliged and we shared a pack of 20 "luxury" baubles between us. In fact any bauble will work as the pattern is flexible and you can't see the bauble underneath after you've finished it.
1. Try to keep a good consistent tension whilst working the two parts of your bauble. If you crochet loosely and consider changing your hook size - you don't want a baggy bauble!
2. The pattern is flexible so if you find your bauble is smaller than the pattern calls for you can easily omit round five and skip straight to round six to ensure your two pieces of crochet fabric cover the bauble perfectly.
3. Swap the thread that the bauble comes with for an an organza ribbon or something similar - this will give the bauble a better finish.
If you haven't made a crochet bauble yet, I heartily recommend them as quick and effective gifts. R's teachers and teaching assistants will be receiving them this year along with some locally-produced chocolates - I hope they like them!